“What a volcano does is put sulfur dioxide into the stratosphere,” Frank Keutsch said. “And that gets oxidized on the scale of weeks to sulfuric acid. “Sulfuric acid,” he continued, “is a very sticky molecule. And it starts making particulate matter—concentrated sulfuric acid droplets—usually smaller than one micron. These aerosols stay in the stratosphere on the timescale of a few years. And they scatter sunlight back to space.” The result is lower temperatures, fantastic sunsets, and, on occasion, famine.
